The present invention relates to a package for a stack of sheets of light sensitive material and, more particularly, to such a package which can be loaded in different kinds of equipment having mechanisms for removing the package material from either of two adjacent sides of the sheets.
It is known to provide packages for rectangular sheets of X-Ray film and to load such packages into equipment which removes the package material from the stack of sheets so that the sheets can be fed seriatim for exposure, etc. A package of this kind is disclosed in U.S. Pat. No. 4,909,389, issued Mar. 20, 1990 in the name of H. S. Plessers et al. The package described in such patent includes a U-shaped cardboard wrapper that is placed around a stack of film sheets, and then the sheets and wrapper are covered by a sleeve of flexible packaging material that is open at one end and has a seal at the other end. The open end is folded and taped to the top of the package and the open end can be released after it is placed in a magazine. The sealed end of the package has a flap projecting from the seal. When the package is placed in a magazine, the flap is engaged with a spindle and the open end is unfolded so that rotation of the spindle pulls the sleeve away from the wrapper and sheets of film, thus leaving the sheets within the magazine where they can be removed seriatim for exposure. The film sheets are shown as rectangular in shape and the sleeve is removed by pulling the sleeve from one of the longer side edges of the rectangular sheets of film.
Another similar package is disclosed in U.S. Pat. No. Re. 28,438, which issued on June 3, 1975 in the name of G. Schmidt. This package includes a light proof envelope or bag containing a stack of rectangular x-ray film sheets. The envelope is sufficiently long so that its leading and trailing edges extend beyond the leading and trailing edges of the narrow side of the film sheets in the envelope. A hole in the leading edge of the envelope is engageable by a pin or mandrel for removing the envelope from the stack of sheets. When the film package is inserted into a dispenser machine, the leading end is attached to the mandrel or to a rotatable bar, and the trailing end is cut by a knife. Then the envelope is pulled from the stack of films along the narrow side edge of the stack of films.
The two patents discussed above are examples of packages for stacks of rectangular sheets of film in which the package material is removed from the stack along the narrow edge of the sheets in one kind of equipment or from along the wide edge of the sheets in another kind of equipment. Because the package material is removed after the package is placed in the equipment, such film packages have been designed for use in only one of the two kinds of equipment, and thus are not universally acceptable in both kinds of equipment. This is true even though the film in the packages may be used in either kind of equipment.
Also, in some kinds of equipment it is important that the film package also be oriented so that the emulsion side of each sheet of film faces in one direction (upwardly) or in the opposite direction (downwardly). Thus, when the sheets of film are oriented so that the emulsion faces upwardly, the flap which is engaged for removing the package material may be folded onto the side of the package facing the emulsion side of the film sheets. In this way it will be readily apparent to the operator that the package is properly oriented in the equipment to assure that the emulsion side faces upwardly, or in some other predetermined direction. Similarly, when the emulsion side is to face downwardly the flap may be folded and secured to the side of the package that is opposite from the emulsion side of the film so that the operator will correctly orient the package within the equipment.
The need for removing package material from different side edges of the film stack, and the different orientation required for film packages in different kinds of equipment has resulted in uniquely different packages for each kind of equipment even though the film sheets used by the different kinds of equipment may essentially be identical and interchangeable. This complicates manufacturing and packaging of the film, increases the inventory of packages required by the manufacturer and user of the packages, and thus increases costs incurred by the manufacturer and by the purchaser of the film packages.